1. Field of the Invention
The present invention relates to a process for the preparation of benzonitrile compounds as described in U.S. Pat. No. 5,127,935 and JP-5-186436A, which are useful as herbicides and their intermediates.
2. Description of the Background
A process for the preparation of benzonitrile compounds is described in JP-9-48761A. Since the process includes the use of copper cyanide as a cyanizing agent, the industrial application thereof has the following problems. The treatment of a waste fluid is troublesome since the waste fluid contains copper which is one of the metals designated in Water Pollution Control Law. In addition, copper cyanide is expensive. Accordingly, the improvement of the above process has been demanded.